Director James Cameron contacted Orson Scott Card before filming began with the possibility of producing a book based on the film. Orson Scott Card initially told his agent that he doesn't do "novelizations", but when she told him that the director was Cameron, he agreed to consider it. The script arrived, and Card signed on after receiving assurances from Cameron that he would be free to develop his "novel" the way he wanted to. After a meeting with Cameron, the author immediately wrote the first three chapters, which dealt with events concerning Bud and Lindsey Brigman that occurred before the events in the film. Cameron gave these chapters to Ed Harris and Mary Elizabeth Mastrantonio, who used it to develop their characters.

Cast members had to become certified divers before filming began.

The masks were specially designed to show the actors' faces, and had microphones fitted so that dialogue spoken at the time by the actors could be used in the film. The noises made by the regulators in the helmets were erased during sound post-production.

Very few scenes involved stuntpeople. When Bud drags Lindsey back to the rig, that's really Mary Elizabeth Mastrantonio holding her breath. When the rig is being flooded and characters are running from water, drowning behind closed doors, and dodging exploding parts of the rig, those are all actors, not stuntpeople.

The scene with the water tentacle coming up through the moon pool was written so that it could be removed without interfering with the story, because no one knew how the effect would come out. The actors were interacting with a length of heater hose being held up by the movie crewmen. When the effects were completed, they surpassed everyone's wildest hopes.

During the TV news report of the US and Russian ships colliding, the accompanying pictures are actually those taken of ships from the British Task Force hit during the Falkland Islands campaign.

Most of the underwater filming took place in a half-completed nuclear reactor facility in Gaffney, South Carolina, including the largest underwater set in the world at 7 million gallons.

The crew frequently spent enough time underwater to force them to undergo decompression before surfacing. James Cameron would often watch dailies through a glass window, while decompressing and hanging upside down to relieve the stress on his shoulders from the weight of the helmet.

The tank was filled to a depth of 40 feet, but there was still too much light from the surface, so a giant tarpaulin and billions of tiny black plastic beads were floated on the surface to block the light. During a violent storm the tarpaulin was destroyed, thus shifting production to night time.

Fluid breathing is a reality. Five rats were used for five different takes, all of whom survived and were given shots by a vet. The rat that actually appeared in the film died a few weeks before the film opened.

The Abyss is the first movie released under the THX Laserdisc Program.

The airline version of The Abyss was supervised by James Cameron himself and runs 118 minutes. Since you can't show a vehicle crashing in a movie shown on an airplane, all of the opening scenes of the submarine incident had to be removed and the title sequence changed (the airline version begins with shots of helicopters landing at the rig). The same version has been used for network TV showings.